1. Field of the Invention
The present invention is generally directed to liquid propane powered forklift trucks and, more specifically, to a fuel tank cradle device for forklift trucks, which enables a fuel tank to be lowered to as near the ground as possible, thereby assuring easy and safe change of the fuel tank.
2. Description of the Prior Art
As is generally known in the art, conventional forklift trucks include a vehicle frame, a mast attached to the front end of the vehicle frame, a fork carriage adapted for elevational movement along the mast to raise and lower loads and a counterweight located at the rear end of the vehicle frame for retaining balance of the forklift truck as heavyweight loads are lifted up and lowered down. Mounted substantially at the center of the vehicle frame is an engine which will be kept covered with a hood or bonnet. A driver""s seat is fixedly secured to the hood and surrounded by an overhead guard which defines a cabin of the trucks. In case of a liquid propane powered forklift truck, it would be necessary to replaceably mount a fuel tank, e.g., liquid propane tank, over the counterweight in a manner that the fuel tank lies on its side and is tied up with a bander or clamp. At the time when the fuel tank runs dry, the bander is untied to permit replacement of the fuel tank with a full one.
There occur frequently such instances where the hood is opened for the operator to gain access to an engine room provided under the hood. The fuel tank held above the counterweight will at this time hinder the backward swing of the seat and thus heavily restrict the opening angle of the hood. In other words, the hood cannot be fully opened without removing the fuel tank prior to the backward opening of the hood. To assure that the hood be opened to its full opening angle, therefore, it is required to remove the fuel tank beforehand into a position wherein no physical interference may take place between the seat and the fuel tank.
As a solution to this problem, use has been made of a fold-back type fuel tank mount that enables a fuel tank to be moved rearwardly from its home position in advance of a hood being opened. The fold-back type fuel tank mount includes a base plate attached to a counterweight of the forklift truck, a swingable cradle lying above the base plate and having a bander with which the fuel tank may be tied up, a hinge for coupling the swingable cradle to the base plate and a latch adapted to retain the swingable cradle against any unwanted swinging movement with respect to the base plate.
In operation, pulling backward the fuel tank with the latch released will cause the swingable cradle to turn rearwardly about a horizontal hinge axis so that the fuel tank is removed out of the home position to permit full opening of the hood.
Due mainly to the heavyweight nature of the fuel tank, the fold-back type fuel tank mount stated above tends to pose a drawback in that, in the process of swinging the cradle together with the fuel tank, a significant magnitude of mechanical shock may occur with the result that parts or components are subjected to deformation and even breakage. An attempt has been made to avoid such drawback in U.S. Pat. No. 5,634,665, which discloses a sliding type fuel tank mount including a fixed plate attached to the counterweight of a forklift truck and a movable plate supporting the fuel tank thereon and adapted for backward sliding movement with respect to the fixed plate to leave a room for accommodation of a seat-carrying hood when the latter is to be opened.
With the prior art fuel tank mounts as referred to hereinabove, as the fuel tank runs dry, it is usually the responsibility of the operator to replace the empty tank with a full one. This requires six steps: (i) Disconnect a feed hose leading from the tank to an engine; (ii) Unclamp the empty tank from its cradle; (iii) Lift and remove the empty tank; (iv) Lift a new tank and place it is the cradle; (v) Clamp the new tank in place; and (vi) Connect the feed hose to the new tank.
The tank replacing procedure entails a difficult and potentially dangerous task. The main difficulty with this procedure lies in steps (iii) and (iv) wherein the operator must lift the fuel tank from the ground to a height of 120 cm or more. Empty liquid propane tanks normally weight between 8.5 and 22 kg, full tanks weighing about 17.5 to 41 kg. With the fuel tank held at chest level or higher, the operator has to extend the tank over the counterweight to drop it into the cradle, in which process the risk of injury to the operator is significant. Some operators consider heaving the tank onto the truck to be a xe2x80x9cmachoxe2x80x9d part of the job. But with more women drivers being hired and the tightening of union rules and government safety regulations, there is a need for an improved fuel tank mount that eases the task of loading and unloading fuel tanks.
In consideration of such a problem, U.S. Pat. No. 5,806,892 discloses a fuel tank mount for forklift trucks with a swing arm swingable about a tilted pivot axis, which enables a fuel tank to be replaced with ease. The fuel tank mount includes a swing arm replaceable carrying the fuel tank, which is pivotally mounted to a tilted pivot pin for rotation between a home position wherein the tank is held above and laterally across the counterweight and a tank changing position wherein the tank lies alongside the counterweight. In the fuel tank mount of the construction referred to just above, the fuel tank is replaced with a new one in a state where the swing arm is located at the tank changing position, and the swing arm is rotated to its original position, the home position, so that the new fuel tank can be held above the counterweight. In this way, the fuel tank mount enables a fuel tank to be more easily replaced.
It is an object of the present invention to provide a fuel tank cradle device for forklift trucks which enables a fuel tank to be lowered to as near the ground as possible in a substantially vertical posture, thereby assuring easy and safe change of the fuel tank.
With this object in view, there is provided a fuel tank cradle device for forklift trucks, comprising: a counterweight; a cradle including a first body and a second body, the first body pivotally mounted to the counterweight for rotation between a home position above the counterweight and a rotated position outside of the counterweight, the second body capable of replaceably supporting a fuel tank and foldably connected to the first body so that the second body can be moved between an unfolded position and a downwardly folded position; and a locking means for locking the cradle to the counterweight while the first body of the cradle is at the home position.